So-called oxidation dyes, wherein a color-developing material is combined with a coupling agent, have been widely used in dyeing keratin fibers such as the hair. In the case of such an oxidation dye, a so-called oxidation pigment, which has been formed by the oxidation coupling of a color-developing material with a coupling agent, would intensely dye, for example, the hair.
Known examples of the color-developing material include p-phenylenediamine derivatives, p-aminophenol derviatives, diaminopyridine derivatives, 4-aminopyrazolone derivatives and heterocyclic hydrazone derivatives; while known examples of the coupling agent include .alpha.-naphthol, o-cresol, m-cresol, 2,6-dimethylphenol, 2,5-dimethylphenol, 3,4-dimethylphenol, 3,5-dimethylphenol, benzcatechin, pyrogallol, 1,5-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 5-amino-2-methylphenol, hydroquinone, 2,4-diaminoanisole, m-toluylenediamine, 4-aminophenol, resorcin, resorcin monomethyl ether, m-phenylenediamine, 1-phenyl-3-methyl-5-pyrazolone, 1-phenyl-3-amino-5-pyrazolone, 1-phenyl-3,5-diketopyrazolidine, 1-methyl-7-dimethylamino-4-hydroxyquinolone-2,1-amino-3-acetylacetamino-4- nitrobenzene, 1-amino-3-cyanoacetylamino-4-nitro-benzene, m-aminophenol, 4-chlororesorcin, 2-methylresorcin, 2,4-diaminophenoxyethanol, 2,6-diaminopyridine, 3,5-diamino-trifluoromethylbenzene, 2,4-diaminofluorobenzene, 3,5-diaminofluorobenzene, 2,4-diamino-6-hydroxypyrimidine, 2,4,6-triaminopyrimidine, 2-amino-4,6-dihydroxypyrimidine, 4-amino-2,6-dihydroxypyrimidine, 4,6-diamino-2-hydroxypyrimidine, p-nitro-o-phenylenediamine, 2-amino-5-nitrophenol, p-nitro-m-phenylenediamine, o-nitro-p-phenylenediamine and 2-amino-4-nitrophenol.
However known oxidation dyes are unsatisfactory in chroma, dyeability power and fastness. Since these properties largely depend on the properties of the employed coupling agents, it is highly important in the preparation of an excellent oxidation dye to find out a material which is excellent as a coupling agent.